Most solid state disks (SSD) are implemented by means of a non-volatile random access storage medium, namely, a NAND flash, where NAND Flashes may be classified into a single level cell (SLC) and a multi-level cell (MLC). The NAND Flash is usually formed by an internal memory and a storage matrix. The storage matrix includes a plurality of blocks, each Block includes a plurality of pages, and each Page further includes a plurality of bytes. Currently, NAND Flashes on the market mostly use MLC chips, and operations on a NAND Flash mainly are read, write, and erase. Read and write is performed on the NAND Flash in a unit of page, and erase is performed in a unit of block. Before a write operation is performed, an erase operation should be performed on a page, and in an erase and write process, an insulation layer of a floating-gate transistor inside the NAND Flash may be damaged. When the erase operation fails, the NAND Flash may actively send a report to the SSD, so that the SSD sets a Block, an operation on which fails, to a bad block. As a quantity of times of erase and write (which is also referred to as a PE Cycle) on the NAND Flash increases, when a percentage of a quantity of bad blocks reaches a threshold, for example, 3%, it is considered that a service life of the NAND Flash ends.
In order to avoid that the service life of the SSD is shortened because bad blocks occur when frequent erase and write operations are performed on some hotspot Blocks, a load balancing technology is introduced in the prior art, and a balancing table is used to record a quantity of times of erase and write on each Block. Each time data is written, an operation is performed preferentially on a Block having a smaller quantity of times of erase and write, thereby ensuring that quantities of times of erase and write of Blocks in the entire SSD are on a same level, that is, the quantities of times of erase and write of Blocks are balanced as much as possible. In addition, some redundant Blocks in the SSD are used as reserved blocks, and when a bad block occurs, a reserved block is used to replace the failed Block, thereby avoiding that the entire SSD expires too early, and extending the service life of the SSD.
Assuming that the SSD has 32000 Blocks, when data is written, the 32000 Blocks are selected evenly, thereby ensuring that quantities of times of erase and write of the blocks are approximate, for example, data write is completed by means of 32000×3K times of operations. However, different Blocks have different service lives. In a data write process, if some Blocks become bad blocks before 3K times of write are performed, the redundant Blocks are used to replace the bad blocks. When the redundant Blocks are used up, the service life of the SSD ends.